The delivery total for 2015 represents an increase of 60 percent over the 2014 total of 31,655 Model S cars.

While it still refuses to report standard monthly U.S. sales like other carmakers, Tesla Motors now reports quarterly global deliveries of its electric cars within a few days after the close of the quarter.

During the third quarter of last year--July through September--Tesla said last week that it delivered 11,580 cars, all but six of them presumably the Model S.

As the company has worked to get its Model X into volume production, financial analysts have focused much attention on the pace of the production increase.

The company had earlier guided analysts to expect Q4 delivery numbers of 17,000 to 19,000 units, so the final figure was on the low side of the midpoint of its average.

While Model X deliveries may have been lower than some hoped, the company said its 17,192 Model S cars in the fourth quarter represented deliveries 75 percent higher than the same quarter of 2014.

That number was also an all-time quarterly record, 48 percent above the previous highest quarter's deliveries for the Model S.

It's worth noting that Tesla's production of more than 50,000 electric vehicles in the U.S. far exceeded the volumes for the domestically produced Nissan Leaf and Chevrolet Volt.

Those two vehicles are likely to end 2015 with sales of perhaps 18,000 and 15,000 respectively.

Still, more than a year ago, CEO Elon Musk said Tesla hoped to enter 2016 at a production rate of 2,000 cars per week, split between the Model S and Model X.

Thus far, it remains some distance from that goal.

EDITOR'S NOTE: An earlier version of this article used an incorrect figure of "about 35,000" for Tesla's 2014 deliveries. That number referred to its 2014 production; the correct number for 2014 deliveries is 31,655. We apologize for the error.